Automatic winding mechanism for quarter hour striking clocks

ABSTRACT

A CLOCK HAVING A CAM MEANS CONTROLLED QUARTER HOUR STRIKING MECHANISM AND SPRINGS FOR THE CLOCKWORK DRIVE AND THE HOUR STRIKING MECHANISM, IN WHICH THE QUARTER HOUR STRIKING MECHANISM IS OPERATED BY AN ELECTROMOTOR SUPPLIED WITH POWER, FOR INSTANCE FROM A BATTERY, AND IN WHICH A SWITCH IN THE ELECTRIC CIRCUIT CONNECTING THE BATTERY TO THE MOTOR IS OPERATED BY THE CAM MEANS CONTROLLING THE QUARTER HOUR STRIKING MECHANISM TO ENERGIZE THE MOTOR   DURING OPERATION OF THE QUARTER STRIKING MECHANISM, THE MOTOR WHEN ENERGIZED, WINDING THE SPRINGS OF THE CLOCK WORK DRIVE AND THE HOUR STRIKING MECHANISM.

R. HERMLE 3,625,000

AUTOMATIC WINDING MECHANISM FOR QUARTER HOUR STRIKING CLOCKS Filed May 4, 1970 4 Sheets-Sheet 1 IN V FIN TOR. flu/m; He'll/4P Dec. 7, 1971 R. HERMLE 3,625,000

AUTOMATIC WINDING MECHANISM FOR QUARTER HOURSTRIKING CLOCKS Filed May 4, 1970 4 Sheets-Sheet 2 Dec. 7, 1971 HERMLE 3,625,000

AUTOMATIC WINDING MECHANISM FOR QUARTER HOUR STRIKING CLOCKS Filed May 4, 1970 4 Sheets-Sheet 5 Ill/Z IN V ENTOR. Rump llEl/ME div/ M5 964! Dec. 7, 1971 R. HERMLE 3,625,000

AUTOMATIC WINDING MECHANISM FOR QUARTER HOUR STRIKING CLOCKS H2 QUATER HouR F1 STRIKING MECHANISM BATTERY United States Patent 3,625,000 AUTOMATIC WINDING MECHANISM FOR QUARTER HOUR STRIKING CLOCKS Richard Hermle, Gosheim, Germany, assignor to Franz Hermle & Sohn, Gosheim, Germany Filed May 4, 1970, Ser. No. 34,473 Claims priority, application Germany, May 2, 1969,

P 19 22 405.6 Int. Cl. G04c 1/04 US. C]. 58-41 23 Claims ABSTRACT OF THE DISCLOSURE A clock having a cam means controlled quarter hour striking mechanism and springs for the clockwork drive and the hour striking mechanism, in which the quarter hour striking mechanism is operated by an electromotor supplied with power, for instance from a battery, and in which a switch in the electric circuit connecting the battery to the motor is operated by the cam means controlling the quarter hour striking mechanism to energize the motor during operation of the quarter striking mechanism, the motor when energized, winding the springs of the clockwork drive and the hour striking mechanism.

BACKGROUND OF THE INVENTION The present invention relates to a mechanical clock with a cam controlled quarter hour striking mechanism and a rack controlled hour striking mechanism in which the springs for the clockwork drive and the hour striking mechanism are intermittently wound by means of an electromotor.

Electromotor driven rack controlled striking mechanisms for clocks are known in which the electromotor is energized during operation of the striking mechanism by contacts controlled from the clockwork drive and in which the electromotor is de-energized after the striking mechanism has sounded the last strike.

The present invention relates to a clock with a quarter hour striking mechanism for instance a so-called Westminster striking mechanism with an electrical drive. Strictly mechanically driven clocks with a striking mechanism of the aforementioned kind are usually provided with cam means for controlling the operation of the quarter hour striking mechanism and for starting the hour striking mechanism.

Clocks with a Westminster striking mechanism with an electromotor drive are also known in which the springs of the quarter hour striking mechanism, of the hour striking mechanism, and the clockwork drive are rewound by means of an electromotor by turning the housings in which the springs are located through a perdetermined angle. Such clocks have, due to the intermittently occurring rewinding by the electromotor, a considerably longer operating time as similar clocks with a strictly mechanical drive. However, such clocks are, due to the additional drive required, considerably more expensive,

SUMMARY OF THE INVENTION It is an object of the present invention to provide a clock with a cam controlled quarter hour striking mechanism as well as with a rack controlled hour striking mechanism with an electromotor drive which, as compared to mechanically driven clocks of this type, is neither more complicated nor more expensive than the latter.

With this and other objects in view, the clock, according to the present invention, which has a cam means controlled quarter hour striking mechanism and a rack controlled hour striking mechanism and clock springs for the clockwork drive and the hour striking mechanism, mainly com- 3,625,000 Patented Dec. 7, 1971 prises electromotor means for directly driving the quarter hour striking mechanism, a power supply circuit connected to the electromotor means, switch means in the circuit, means controlled by the cam means for opening and closing the switch means so as to energize the electromotor means during operation of the quarter hour striking mechanism, and winding means for winding the springs for the clockwork drive and the hour striking mechanism connected to the electromotor means to be driven thereby when the electromotor means is energized during operation of the quarter hour striking mechanism.

The arrangement according to the present invention 'will provide for an extremely simple and therefore inexpensive but nevertheless trouble-free operating construction. In addition, the battery operated clock, according to the present invention, will produce winding noise only during operation of the striking mechanism so that the winding noise will be covered by the sound produced by the striking mechanism and in this respect the clock, according to the present invention, differs also advantageously from the known battery operated clocks having a Westminster striking mechanism.

Opening and closing of the switch in the power supply circuit of the electromotor and therewith initiating of the quarter hour striking mechanism is accomplished, according to the present invention, by means of a cam disc mounted on a shaft of the quarter hour striking mechanism and cooperating with a release lever controlled by actuating means on the minute wheel shaft of the clockwork drive. The release lever is provided for this purpose with an arm which actuates the electrical contact in the power supply circuit of the motor. In known mechanical striking mechanisms for clocks of this type, the aforementioned release lever drops immediately after its release into a cutout of the cam disc and is only at the start of the operation of the striking mechanism moved again outwardly of the cutout by a cam surface of the disc. However, since the release lever, according to the present invention, has to control the switch in the circuit of the electromotor, the lever has to be held, according to a further feature of the present invention, at the start and during operation of the quarter hour striking mechanism in its releasing position.

This can, for instance, be accomplished by means of an additional auxiliary lever which holds the release lever in its releasing position until the cam surface of the rotating cam means takes over this function.

According to a preferred arrangement of the present invention, a second or blocking cam disc is provided for this purpose which blocks the cutouts in the first-mentioned cam disc at the start of operation of the quarter hour striking mechanism and which clears the cutouts at the end of this operation and the release lever is provided with a projection which at the start of the operation of the quarter hour striking mechanism engages the second cam disc. In this arrangement, the second cam disc may be coaxially arranged with the first cam discand turnable with respect to the latter under the action of a spring through a predetermined angle. The arrangement is made in such a manner that one or both discs are held by the projection on the release lever against the action of the spring in such a manner that the cutouts in both discs are aligned with each other when the quarter hour striking mechanism is not in operation. If, however, the projection is moved outwardly from the respective aligned cutouts, then the discs will turn with respect to each other under the influence of the spring cooperating therewith so that the cutouts in one disc are overlapped by the solid portions of the other disc. This can be accomplished in various different ways. For instance, the first cam disc may be fixedly connected to a shaft of the quarter hour striking mechanism and the second disc may be turnable relative to the first disc, re-

spectively, the second disc may be fixedly connected to the aforementioned shaft and the first disc may be turnable relative thereto, or both discs may be turnable relative to each other and relative to the shaft. It is also possible to mount each of the two discs on a different shaft or to arrange one of the discs in form of a ring in a corresponding annular cutout of the other disc.

It is also possible to arrange the two cam discs not turnable but movable in axial direction relative to each other.

In a preferred arrangement, according to the present invention, the first cam disc is fixedly connected to a shaft of the quarter hour striking mechanism and the second cam disc which serves as a blocking disc is turnable under the influence of a spring relative to the first disc through a predetermined angle.

According to a further feature of the present invention, the blocking disc is provided adjacent the cutouts formed therein with projecting cam portions which project beyond the periphery of the first cam disc and which are engaged by the projecting portion of the release lever in order to return the blocking disc against the action of the spring to a position in which the cutouts in both discs are aligned with each other.

Basically it is also possible, according to the present invention, to obtained a similar action without the provision of an additional blocking disc, that is, if the cam disc itself is mounted on the shaft of the quarter hour striking mechanism movable in circumferential or axial direction under the action of a spring and in such an arrangement in which the cam disc, under the action of the spring, may suddenly be turned or axially moved, it is also possible to prevent the projection on the release lever at the beginning of the operation of the quarter hour striking mechanism to fall back in the respective cutout of the cam disc which would reopen the switch means again.

According to a further feature of the present invention it is also possible to provide one or both of the cam discs with additional cam portions for controlling of additional striking mechanisms or movement of toy figures connected with the clock. These additional cam portions may be provided on the side faces of the cam discs or be formed cam grooves.

The switch means, according to the present invention, preferably comprise a switch arm carrying a first contact, a second contact and spring means connected to the switch arm for yieldably moving the first contact in engagement with the second contact. The spring-pressed arm of the switch means is engaged by an arm provided on the release lever to normally hold the switch means in open position and the switch arm is released at the start of the operation of the quarter hour striking mechanism so that the switch means will be closed under the influence of the spring cooperating with the switch arm. However, in order to assure that the electromotor is not started at the moment the release lever is moved to its releasing position, a contact blocking lever is provided which holds the switch means in open position for a certain time after the same is released by the releasing lever. Other-wise, the first cam disc, which is rotated during operation of the electromotor, might clamp the projection on the releasing lever. This contact blocking lever amy be mounted on a second releasing lever controlled by a star-shaped cam mounted on the minute wheel shaft of the clock and cooperating with the first-mentioned releasing lever to move the latter to the releasing position at the start of the operation of the quarter hour striking mechanism. Preferably, the arrangement is made in such a manner that the second releasing lever is coupled to the first releasing lever in such a manner that the latter is moved to its releasing position only after the contact blocking lever is moved to a position in which it initially prevents the arm of the switch means to move to the contact closing position.

In order to prevent damage or destruction of the switch means during setting of the hands of the clock during the operation of the quarter hour striking mechanism, the contact blocking lever is preferably tiltably or elastically flexibly mounted on the second releasing lever.

The second contact which cooperates with the contact on the movable switch arm is preferably in the form of a rotary contact disc which may, for instance, be driven by the quarter hours striking mechanism. Since the disc is rotated when the switch is closed, the contact surfaces will be cleaned so that interruption of proper contact due to dirt is practically excluded. In order to assure proper flow of current to the contact disc, the current is not transmitted to the same through the shaft on which the contac disc is mouned, but through a sliding contact, for instance, a contact spring, which in turn is, for instance, connected through the clockwork drive with one pole of the battery respectively one terminal of the motor.

With such an arrangement it is necessary that the switch arm which cooperates with the contact disc is electrically insulated from the releasing levers. For this purpose, a contact control member is connected to the switch arm on which the arm of the first release lever and the contact blocking lever act and the contact control member and/or the arm on the first release lever and the contact blocking lever are formed at least in part from electrically insulating material.

In place of the above-mentioned switch means it is also possible to use other switching devices, for instance, a key-operated high frequency switch for contactless closing and opening the circuit, magnetic contacts, for instance, so-called reed contacts, or electronic switches. The arrangement must be made in such a manner as to prevent blocking of the control means at the end of the striking operation. Since the clockwork drive will, due to the inertia of its movable part, still continue to rotate even after the motor is de-energized, it is possible that the projection on the first release lever, which drops into the respective cutout of the first cam disc, may be clamped in the cutout. In order to preevnt such an occurrence, the first release lever is provided with another projection which in the starting or rest position of the release lever engages a gear of the quarter hour striking mechanism to block the same. In order to prevent, during this operation, damage to the gears, the arrangement, according to the present invention, preferably also provides one or a plurality of clutches in the clockwork drive and in the winding mechanism for the clock springs. Preferably at least one slip clutch is provided in the drive for the quarter hour striking mechanism which is preferably arranged downstream of the drive for the clockwork and the drive for the hour striking mechanism. This will assure that the springs may also be wound during blocking of the quarter hour striking mechanism. In addition to the aforementioned one slip clutch, additional slip clutches may also be provided in the drive for the clockwork and in the drive for the hour striking mechanism.

In order to prevent unwinding of the fully wound springs over the winding mechanism and the motor, the clock of the present invention is provided, according to a further feature, with a blocking or ratchet mechanism in the drive between the electromotor and the spring housings which is arranged preferably immediately after the electromotor or eventually at each of the spring housings. This blocking mechanism is preferably in the form of a silent ratchet mechanism in which the noise resulting from the ratcheting of the pawl is avoided. The ratchet mechanism, according to the present invention, comprises a lifting disc which frictionally engages the ratchet wheel and in which the friction disc is provided with an inclined surface engaging the pawl of the ratchet mechanism during free wheeling and lifting the pawl during free wheeling out of engagement with the teeth of the ratchet wheel against the action of a spring tending to keep the pawl in engagement with the teeth of the ratchet.

In order to wind the springs of the clockwork and of the hour striking mechanism by hand, for instance, at the beginning of the operation of the clock, respectively after exchange of the battery, the present invention provides also for means to manually wind the springs of the clock. Instead, or in addition to the manual winding means, the clock of the present invention may also be provided with an additioanl switch permitting to energize the electromotor at the will of the operator in order to thus wind the springs of the clockwork and of the hour striking mecha- 1115111.

A preferred arrangement, according to the present invention, prevents also undesired reaction of the spring of the clockwork mechanism onto the latter. Usually, the housing of the spring for the clockwork is directly connected to the minute wheel shaft so that in addition to the spring force acting in circumferential direction also a radial force component is imparted to the gear mechanism of the clockwork. This radial component increases in a detrimental manner the bearing friction of the minute wheel shaft.

To overcome this disadvantage, the spring housing of the clockwork is not directly mounted on the minute wheel shaft but on a trunion fixed to the frame of the clock and is drivingly connected by means of one or a plurality of pins fixed to the spring housing and engaging a drive wheel, for instance the minute wheel. In such a connection a transmission of the radial force component resulting from the unwinding spring onto the drive shaft is prevented.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIGS. 1-3 are side views of the control mechanism according to the present invention for controlling operation of the quarter hour striking mechanism and FIGS. 13 show the elements of the control means in successive positions;

FIG. 4 is a front view of the cam discs of the control mechanism according to the present invention;

FIG. 5 is a side view of the elements shown in FIG. 4;

FIG. 6 is a partially sectioned side view of the arrangement of the spring housing of the clockwork and its connection to the minute wheel shaft;

FIGS. 7 and 8 are front views of the silent ratchet mechanism according to the present invention and respectively showing this mechanism in two different positions; and

FIG. 9 is a schematic overall view of the electromotor and its connection to the various components of the clock.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawing, and more specifically to FIGS. 1-3 of the same, it will be seen that the control mechanism, according to the present invention, mainly comprises a star-shaped cam 2 mounted on the minute Wheel shaft 1 of the clock for rotation therewith, a first release lever 4, a second release lever 3 cooperating with the star-shaped cam 2 and the first release lever 4 for operating the same, a first cam disc'5 and a second cam disc or blocking disc 6 cooperating therewith, a springy contact or switch arm 7, a rotating contact disc 8 cooperating therewith, and a contact control member 9 fixed to the free end of the switch arm 7.

The star-shaped cam 2 rotates in clockwise direction, as indicated by the arrow, and serves for control of the striking mechanism of the clock. A pin 3:: connected to one end of the second release lever 3 engages the peripheral surface of the cam disc 2 which is formed as a control curve. The quarter hour striking mechanism is released each time when the pin 3a is raised by means of the teeth 2a, 2b, 2c and 2d of the star-shaped cam 2. One of the four teeth, that is the tooth 2:1, is longer than the remainder of the teeth. This will assure, as will be explained later on in further detail, an automatic regulation of the striking mecahnism, that is, operation of the hour striking mechanism in correspondence with the sequential operation of the quarter hour striking mechanism.

The second release lever 3 which is turnable about the axis 3a is arranged to lift with its right free end 312- the first release lever 4 which is provided for this purpose with a laterally projecting pin 4a located in the path of movement of the end 31) of the second release lever 3. The second release lever 3 is also provided with a contact blocking lever 3e which is turnable about the axis 30 against the action of a spring 3d connected at opposite ends to the levers 3 and 3c.

The first release lever 4, which is turnable about the axis 4b, controls in a known manner, not forming part of the present invention, the hour striking mechanism as well as the quarter hour striking mechanism in the manner as will be explained later on. A pin 4d projecting laterally fro-m the left end, as viewed in FIG. 1, of the first release lever 4 controls the hour striking mechanism by lifting a not illustrated lever out of the teeth of a likewise not illustrated rack of the hour striking mechanism, as for instance disclosed in the German Pat. 1,224,209. A tooth 4c likewise provided on the left end of the first release lever initially locks the hour striking mechanism which is released shortly before stopping operation of the quarter hour striking mechanism until the latter has sounded its last stroke.

The first release lever 4 is provided in a new manner with an arm 4h fixedly connected thereto, which has at its free end a nose 4 acting on a laterally bent portion 9a of the contact control member 9.

A first cam disc 5 is mounted, in the same manner as in a strictly mechanically operated quarter hour striking mechanism, on a shaft 10 of the quarter hour striking mechanism. The cam disc 5 rotates in clockiwse direction when the electromotor is energized and it controls the movement of the first release lever 4, respectively that of the arm 4h connected thereto, by means of a projecting portion thereon, shown in the drawing as a laterally projecting pin 4e. As shown in FIGS. 4 and 5, the first control disc 5 is provided with a plurality of cutouts 5a extending circumferentially spaced from each other inwardly from the peripheral surface thereof and respectively limiting the cam portions on the peripheral surface which determine the duration and sequence of the quarter hour strikes. The cutouts 5a are arranged so that with a suitable, well known and therefore here not further described quarter hour striking mechanism a stroke sequence characteristic for a Westminster striking mechanism is released at each quarter of an hour. In the illustrated embodiment of the cam disc 5, the angle between the first and second cutout is 36, between the second and third 72, between the third and fourth 108, and finally between the fourth and first cutout 144, whereby each of the cutouts extends through an angle of about 6. These dimensions may, however, be varied in accordance with the desired stroke sequence and stroke duration.

The first cam disc 5 is further provided between the fourth and the first cutout with a projecting cam portion 5b which projects radially outwardly beyond the remainder of the peripheral surface thereof and by means of which the first release lever 4 is at the end of each full hour tilted in such a manner so as to release the hour striking mechanism. The flank 5c of this projecting portion is dimensioned so high that the pin 4e on the release lever 4 can only be lifted from the last cutout when the second release lever 3 is lifted by the long tooth 2d of the star-shaped cam 2. This will assure a proper coordination of the sequence of the hour striking mechanism to the striking sequence of the quarter hour striking mechanism.

The second cam disc or blocking disc 6, which is arranged on the shaft 10 turnable with respect to the latter and to the first cam disc 5, is provided with cutouts corresponding to the cutouts of the cam disc 5. A pretensioned spring 11 is connected at opposite ends to pins d and 6a respectively connected to the cam discs 5 and 6 and these pins respectively extend through elongated openings 6b and 5 extending in circumferential direction of the disc and being arranged and dimensioned in such a manner so that portions 6c overlap the cutouts 5a of the cam disc 5 when the spring is untensioned, whereas the spring 11 is in tensioned condition when the cutouts in the two discs are aligned with each other.

Therefore, when the pin 4e on the lever 4 is moved out of the cutouts of the disc 5 and raised beyond the cam portion 6c of the locking disc 6' which project radially beyond the circumference of the cam disc 5, the locking disc will abruptly turn under the influence of the spring 11 to the position shown in FIGS. 2-4. The pin 42 can, therefore, not move back into one of the cutouts of the cam disc 5 so that the release lever 4 is maintained in its deflected position until the pin 4e again engages the flank of one of the cam portions 60 which project beyond the circumference of the cam disc 5. Such engagement will block the locking disc 6 so that the pin 42 during further rotation of the cam disc 5 will drop into the next following cutout.

The switch controlled by the above-described mechanism comprises, as mentioned already, essentially a switch arm 7 which is pressed by the spring 7a, connected thereto against the contact disc 8 when the arm 4h releases the contact member 9 connected to the spring arm. The spring arm 7 carries at the end thereof to which the contact control member 9 is connected, at contact 7b which is adapted to engage the peripheral surface of the contact disc 8 which is rotated by the quarter hour striking mechanism. Current is supplied to the contact disc 8 by means of a sliding contact in form of a spring 8a which engages under spring pressure the rear face of the contact disc 8.

The above-described arrangement will operate as follows:

FIG. 1 illustrates the release levers 3 and 4 in their rest position. The pin 4e of the first release lever 4 is located in one of the cutouts of the cam disc 6 and 5 which are aligned with each other. In this position, the nose 4 on the arm 4h of the first release lever 4 engages the contact control member 9 to hold the switch 7, 8 in open position and the electromotor connected in circuit with the switch is thereof de-energized.

When the star-shaped cam 2 mounted on the minute wheel shaft 1 is turned to the position as shown in FIG. 2, the second release lever 3 is tilted in counterclockwise direction which will first move the free end of the contact blocking lever 3e to a position opposite of the surface 9b of the contact control member 9, and only subsequently thereto will the free end 3b of the second release lever 3 engage the pin 4a on the first release lever so as to tilt the latter in clockwise direction about its axis 4b, lifting thereby the pin 4e out of the cutouts in the cam disc 5 and 6 and simultaneously moving the nose 4 on the arm 4h connected to the first release lever out of engagement with the portion 9a of the contact control member. However, the switch is still held in open position due to the engagement of the free end of the contact blocking lever 3e with the surface 9b of the contact control member 9.

Only after the star-shaped cam disc 2 is turned from the position shown in FIG. 2 to that shown in FIG. 3 will the second release lever 3 move to its starting position so that the contact blocking lever 3e will release the contact control member 9, whereupon the contact 711 on the contact arm 7 will move under the influence of the spring 7a in contact with the peripheral surface of the contact disc 8 to thereby close the switch and energize the electromotor so that the latter will drive the shaft 10 of the quarter hour striking mechanism.

The contact blocking lever 3e assures therefore that the switch is closed and the cam disc 5 rotated only after the pin 4e is moved out of the cutouts of the two cam discs and after the cutouts in the cam disc 5 are blocked by portions of the blocking disc 6.

The contact blocking lever 32 is tiltably mounted on the lever 3 in order not to damage the arrangement when the hands of the clock are adjusted during operation of the quarter hour striking mechanism. The spring 3d holds the contact blocking lever 3 in its normal operating position.

In the position of the various elements of the control arrangement as shown in FIG. 3 in which the blocking disc 6 has assumed its blocking position and in which the second release lever 3 has returned to its rest position, the pin 4e on the first release lever 4 engages one of the cam portions 6c of the blocking disc 6. The lever 4 is thereby held in its releasing position so that the switch means 7, 8 remains closed. The switch is reopened again only when the pin 4e of the lever 4 falls in the next following cutouts of the discs 5 and 6 whereby the arm 4h with its nose 4 is tilted into engagement with portion 9a of the contact control member 9 to thereby open the switch. The first release lever 4 may be constructed to move when released from its releasing position shown in FIGS. 2 and 3 to its rest position shown in FIG. 1 under the influence of gravity, or under the influence of a spring, not shown in the drawing.

The first release lever 4 is further provided, as shown in FIGS. 1 and 3, with a laterally and rearwardly bent portion 4g located in the path of a pin 12 on a non-illustrated wheel of the quarter hour striking mechanism when the lever 4 is in its rest position. The portion 4g assures therefore that the drive gears of the quarter hour drive mechanism at the end of the operation of the latter, that is after de-energizing the electromotor driving the same, is suddenly stopped. Otherwise, these gears could turn further under the influence of their inertia which would glamp the pin 4e on the lever 4 in the cutouts of the isc 5.

In order to prevent reactions of the clockwork drive onto the minute wheel shaft, the housing 12 of the spring for clockwork drive is mounted on a bushing 15 which, in turn, is turnably mounted on a separate trunnion 13 which is fixed to the frame plate 14 of the clock, as shown in FIG. 6. The non-illustrated spring is arranged between the bushing 15 and the housing 12. The minute wheel shaft 1 is turnably mounted between the front plate 16 and the the trunnion13, whereby a reduced end portion 1a of the shaft 1 is mounted in a bearing bushing 13a which, in turn, is located in a bore 13b formed at the front end of the trunnion 13. A pin 17 fixed to and projecting laterally from the spring housing 12 extends through a radial slot in a gear 18, mounted rotatably on the shaft 1. The cup spring 19 is arranged between and pressed against a flange on the shaft 1 and the gear 18, being a slip clutch between shaft 1 and gear 18. The pin 17 thus couples the spring housing 12 to the gear 18. This mounting of the spring housing 12 will assure that the coupling pin 17 will transmit only the spring force which acts in circumferential direction but not in radial direction acting force components which would lead to an increase of the bearing friction. The outer end of the not shown spring is connected to the spring housing and the inner end to the bushing 15 which carries outside the spring housing the winding gear 20 by means of which the spring is wound over a gear transmission from the electromotor.

FIGS. 7 and 8 illustrate the silent locking or ratchet mechanism provided in the gear transmission downstream of the electromotor and preventing unwinding of the wound spring over the rotor of the electromotor when the latter is not energized. This silent ratchet mechanism v comprises a toothed ratchet gear 21 and a lifting disc 23 mounted on the shaft 22 of the ratchet gear and in frictional engagement therewith, for instance by being pressed by a nonillustrated spring with a side face thereof against the corresponding side face of the ratchet gear 21. A pawl 24 turnable about a pivot pin 24a has a laterally bent portion 240 normally held in engagement with the teeth of the ratchet gear 21 by a tension spring 24b acting on the end of the pawl 24 opposite to the end of which the laterally bent portion 240 is provided. The lifting disc 23 is provided with a nose 23a located beneath the lateral portion 240 of the pawl and the nose 23a has a steep flank connected by an inclined surface ortion 23b to the circumferential surface of the disc 23. The laterally bent portion 240 of the pawl 24 engages under the influence of the spring 24b of the aforementioned inclined surface 231;. During rotation of the ratchet gear 21 in clockwise direction, the lifting disc 23 is rotated therewith in the same direction and lifts the pawl 24 by means of the inclined surface 23b out of engagement with the teeth of the ratchet wheel, as shown in FIG. 8, so

. that the ratchet wheel may freely rotate in clockwise direction. The lifting disc 23 is held in the position in which it lifts the ratchet pawl out of engagement with the ratchet wheel during further rotation of the ratchet gear in clockwise direction due to the frictional engagement between the ratchet gear 21 and the lifting disc 23. However, during rotation of the ratchet gear 21 in counterclockwise direction the lifting disc 23 will also be taken along until its nose 23a abuts against the pin 24a and the pawl 24 is thereby freed so that the laterally bent portion 24c of the pawl will again engage the teeth of the ratchet wheel 21 and block the latter.

As compared with known silent ratchet mechanisms, the ratchet mechanism, according to the present invention, is characterized by an extremely simple construction suitable for mass fabrication.

FIG. 9 shows in a schematic manner the overall arrangement of the clock, according to the present invention. The electromotor M drives over its drive shaft S and gear transmissions T T and T respectively, the spring housings H and H of the clockwork and the hour striking mechanism and the quarter hour striking mechanism. A ratchet mechanism R as described in connection with FIGS. 7 and 8 is provided behind the shaft S of the motor to prevent unwindings of the springs of the clockwork and the hour striking mechanism over the rotor of the electromotor M when the latter is not energized. Thus displacing at the quarter hour striking mechanism is prevented. There is provided a slip clutch F located between the shafts of the motor and the quarter hour striking mechanism in the gear transmission T Additional slip clutches F and F may be provided between the gear transmissions T and the spring housing H respectively between the gear transmission T and the spring housing H Manual winding means W are preferably provided between the gear transmissions T and T for both of the spring housings permitting manual winding of the springs located therein. The switch means 7, 8 described in connection with FIGS. 1-3 are operated from the quarter hour striking mechanism in the manner as described in connection with the aforementioned figures. A manually operable switch 30 may be provided in parallel to the switch means 7, 8 in the circuit which connects the battery to the electromotor M. The showing of FIG. 9 is strictly schematic and is not intended to illustrate the actual gear transmissions between the shaft of the motor and the other elements illustrated in FIG. 9.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of clocks diifering from the types described above.

10 nism is operated by an electric motor, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

1. In a clock having a cam means controlled quarter hour striking mechanism hour striking mechanism and clock springs for the clockwork drive and the hour striking mechanism, a combination comprising electromotor means for directly driving said quarter hour striking mechanism; a power supply circuit connected to said electromotor means; switch means in said circuit; means controlled by said cam means for opening and closing said switch means so as to energize said electromotor means during operation of said quarter hour striking mechanism; and winding means for winding the springs for said clockwork drive and hour striking mechanism connected to said electromotor means to be driven thereby when said electromotor means is energized during operation of said quarter hour striking mechanism.

2. A combination as defined in claim 1, wherein said clockwork drive comprises a minute wheel shaft and wherein said means for opening and closing said switch means comprise first release lever means movable between a rest position and a releasing position permitting closing of said switch means, and actuating means cooperating with said minute wheel shaft for moving said first release lever means to said releasing position at the start of operation of said quarter hour striking mechanism and said cam means cooperating with said first release lever means for maintaining the latter in said releasing position for the duration of operation of the quarter hour striking mechanism.

3. A combination as defined in claim 2, and including a drive shaft for said quarter hour striking mechanism, said cam means comprising at least one cam disc mounted on said drive shaft for limited movement relative thereto, said one cam disc having a radially outwardly projecting cam portion, biassing means cooperating with said one cam disc for moving the same relative to said shaft, said first release lever means having a projecting portion engaging said outwardly projecting cam portion of said one cam disc at the start of operation of said quarter hour triking mechanism.

4. A combination as defined in claim 3, wherein said cam means have in addition to said one radially outwardly projecting portion additional control portions for controlling movement of elements of said clock different from said first release lever means.

5. A combination as defined in claim 2, wherein said cam means comprise a first cam disc having a peripheral cam surface and a plurality of circumferentially spaced cutous extending inwardly from said cam surface, said first release lever means having a projecting portion located in said rest position of said lever means in one of said cutouts, and means for blocking said cutouts at least at the start of operation of said quarter hour striking mechanism and for clearing said cutouts at the end of said operation, said projecting portion engaging said blocking means at least at the start of said opera ion.

6. A combination as defined in claim 5, wherein said blocking means comprises a second cam disc coaxial with and having the same cutouts as said first cam disc, and biassing means cooperating with at least one of said discs for turning the same relative to the other disc 11 through a limited angle about the common axis, said projecting portion when located in one of said cutouts of said first cam disc holding the second cam disc against the force of said biassing means in a position in which -said cutouts in the two discs are substantially aligned with each other.

7. A combination as defined in claim 6, and including a drive shaft for the quarter hour striking mechanism, said first cam disc being fixedly mounted on said drive shaft and said second cam disc being mounted on said drive shaft turnable through said limited angle relative to said first cam disc and provided adjacent the cutout thereof with portions projecting beyond the periphery of said first cam disc and respectively engaging said projecting portion of said first release lever means at the end of the movement of said discs relative to each other.

8. A combination as defined in claim 7, wherein said actuating means comprise a star-shaped cam fixed to said minute wheel shaft for rotation therewith, second release lever means controlled by said star-shaped cam and cooperating with said first release lever means for moving the latter at the start of the quarter hour strik ing mechanism operation from said rest to said releasing position, wherein said switch means comprise a switch arm carrying a first contact, a second contact, and spring means connectedto said switch arm for yieldably moving said first contact in engagement with said second contact, said first release lever means having an arm cooperating with said switch means for maintaining the latter in open position during the time said quarter hour striking mechanism is not in operation, and including contact blocking lever means mounted on said second release lever means and movable by the latter to a blocking position in which it cooperates with said switch means for holding the same in said open position until said projecting portions on said first release lever means is moved out of the respective cutout of said first cam disc.

9. A combination as defined in claim 8, and including coupling means on one of said release lever means and engaging the other of said release lever means for moving said first release lever means to said releasing position only after said contact blocking lever means have been moved to said blocking position.

10. A combination as defined in claim 9, wherein said contact blocking lever means is pivotally mounted on said second release lever means and including spring means between said blocking lever means and said second release lever means for normally holding the same in a predetermined position relative to each other.

11. A combination as defined in claim 10, wherein said second contact comprises a rotary contact disc driven by said quarter hour striking mechanism.

12. A combination as defined in claim 11, and including a sliding contact engaging said contact disc for connecting the same to said power supply circuit.

13. A combination as defined in claim 11, wherein said switch means comprise further a contact control member cooperating with said arm of said first release lever means and said contact blocking lever means, at least said contact control member being of insulating material.

12 14. A combination as defined in claim 13, wherein said first release .lever means has a second projecting portion which in the rest position of said first release lever means is adapted to block the drive of said quarter hour striking mechanism.

15. A combination as defined in claim 14, and including at least one slip clutch between said motor, said quarter hour striking mechanism and said winding mechanism.

16. A combination as defined in claim 15, wherein said at least one slip clutch is arranged between said motor and said quarter hour striking mechanism downstream of said winding mechanism.

17. A combination as defined in claim'16,=wherein an additional slip clutch is provided in said winding mechanism.

18. A combination as defined in claim 1, and including a housing for each of said springs operatively connected to said electromotor means and at least one ratchet mechanism between said electromotor means and said housings.

, 19. A combination as defined in claim 18, wherein a ratchet mechanism is provided for each of said housings. 20. A combination as defined in claim 18, wherein said ratchet, mechanism comprises a ratchet Wheel, a pawl, biassing means for urging said pawl in engagement with said ratchet wheel, and lifting disc means coaxial with and in frictional engagement with said ratchet wheel for disengaging said pawl against the force of said biassing means from said ratchet wheel during rotation of the latter in one direction.

21. A combination as defined in claim 1, and includ ing means connected to each of said springs for manually winding the same.

22. A combination as defined in claim 1 and including an additional switch in said circuit for closing the same at the will of the operator.

23. A combination as defined in claim 1, and including a frame, a trunnion fixed to said frame, said winding means comprising a shaft coaxial with said trunnion and driven by said electromotor means, a housing for the spring of the clockwork. drive freely turnably mounted on said trunnion, a wheel mounted on said shaft for turning therewith and coupling means coupling said wheel 5 to said housing for simultaneous rotation.

References Cited UNITED STATES PATENTS 1,140,477 5/1915 Myrick 5841 A 1,924,116 8/1933 Fowler 5'8'41B 2,128,563 8/1938 Schneider 5841 B 3,258,086 6/1966 Romo 5846 X 3,276,199 10/1966 Ishikawa 5841 5 RICHARD R. WILKINSON, Primary Examiner L. R. FRANKLIN, Assistant Examiner US. Cl. X.R.

60 589, 46; -40 K; 200 35 R, 38 R 

